Retaining Mechanisms for Prosthetic Valves

ABSTRACT

Disclosed herein are representative embodiments of methods, apparatus, and systems used to deliver a prosthetic heart valve to a deficient valve. In one embodiment, for instance, a support stent is delivered to a position on the surface of the outflow side of a native heart valve of a patient, the support stent defining a support-stent interior. An expandable prosthetic heart valve is delivered into the native heart valve from the inflow side of the native heart valve and into the support-stent interior. The expandable prosthetic heart valve is expanded while the expandable prosthetic valve is in the support-stent interior and while the support stent is at the position on the surface of the outflow side of the heart valve, thereby causing one or more of the native leaflets of the native heart valve to be frictionally secured between the support stent and the expanded prosthetic heart valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.12/368,891, filed Feb. 10, 2009, which claims the benefit of U.S.Provisional Application No. 61/074,597 filed Jun. 20, 2008, and U.S.Provisional Application No. 61/088,947 filed Aug. 14, 2008, both ofwhich are hereby incorporated herein by reference.

FIELD

This application relates to methods, systems, and apparatus for safelyreplacing native heart valves with prosthetic heart valves.

BACKGROUND

Prosthetic heart valves have been used for many years to treat cardiacvalvular disorders. The native heart valves (such as the aortic,pulmonary, and mitral valves) serve critical functions in assuring theforward flow of an adequate supply of blood through the cardiovascularsystem. These heart valves can be rendered less effective by congenital,inflammatory, or infectious conditions. Such conditions can eventuallylead to serious cardiovascular compromise or death. For many years thedefinitive treatment for such disorders was the surgical repair orreplacement of the valve during open heart surgery, but such surgeriesare dangerous and prone to complication.

More recently a transvascular technique has been developed forintroducing and implanting a prosthetic heart valve using a flexiblecatheter in a manner that is less invasive than open heart surgery. Inthis technique, a prosthetic valve is mounted in a crimped state on theend portion of a flexible catheter and advanced through a blood vesselof the patient until the valve reaches the implantation site. The valveat the catheter tip is then expanded to its functional size at the siteof the defective native valve, such as by inflating a balloon on whichthe valve is mounted. Alternatively, the valve can have a resilient,self-expanding stent or frame that expands the valve to its functionalsize when it is advanced from a delivery sheath at the distal end of thecatheter.

Balloon-expandable valves are commonly used for treating heart valvestenosis, a condition in which the leaflets of a valve (e.g., an aorticvalve) become hardened with calcium. The hardened leaflets provide agood support structure on which the valve can be anchored within thevalve annulus. Further, the catheter balloon can apply sufficientexpanding force to anchor the frame of the prosthetic valve to thesurrounding calcified tissue. There are several heart conditions,however, that do not involve hardened valve leaflets but which are stilldesirably treated by valve replacement. For example, aorticinsufficiency (or aortic regurgitation) occurs when an aortic valve doesnot close properly, allowing blood to flow back into the left ventricle.One cause for aortic insufficiency is a dilated aortic annulus, whichprevents the aortic valve from closing tightly. In such cases, theleaflets are usually too soft to provide sufficient support for aballoon-expandable prosthetic valve. Additionally, the diameter of theaortic annulus may continue to vary over time, making it dangerous toinstall a prosthetic valve that is not reliably secured in the valveannulus. Mitral insufficiency (or mitral regurgitation) involves thesesame conditions but affects the mitral valve.

Self-expanding prosthetic valves are sometimes used for replacingdefective native valves with noncalcified leaflets. Self-expandingprosthetic valves, however, suffer from a number of significantdrawbacks. For example, once a self-expanding prosthetic valve is placedwithin the patient's defective heart valve (e.g., the aorta or mitralvalve), it continues to exert an outward force on the valve annulus.This continuous outward pressure can cause the valve annulus to dilatefurther, exacerbating the condition the valve was intended to treat.Additionally, when implanting a self-expanding valve, the outwardbiasing force of the valve's frame tends to cause the valve to beejected very quickly from the distal end of a delivery sheath. Thismakes delivery of the valve very difficult and dangerous to the patient.

The size of the prosthetic valve to be implanted into a patient can alsobe problematic when treating aortic or mitral insufficiency.Specifically, the size of a prosthetic valve used to treat aortic ormitral insufficiency is typically larger than a prosthetic valve used totreat aortic or mitral stenosis. This larger valve size makes thedelivery procedure much more difficult and dangerous to the patient.

Accordingly, there exists a need for improved methods, systems, andapparatus for delivering expandable prosthetic heart valves (e.g.,balloon-expandable prosthetic valves). Embodiments of the methods,systems, and apparatus desirably can be used to replace native heartvalves that do not have calcified leaflets (e.g., aortic valvessuffering from aortic insufficiency). Furthermore, embodiments of themethods, systems, and apparatus desirably enable precise and controlleddelivery of the prosthetic valves.

SUMMARY

Disclosed below are representative embodiments of methods, systems, andapparatus used to replace deficient native heart valves with prostheticheart valves. Embodiments of the disclosed methods, systems, andapparatus can be used, for example, to replace an aortic valve sufferingfrom aortic insufficiency or a mitral valve suffering from mitralinsufficiency. These embodiments are not limiting, however, as thedisclosed methods, systems, and apparatus can be more generally appliedto replace any heart valve.

In certain embodiments, for example, a support structure is delivered toa position on or adjacent to the surface of the outflow side of a nativeheart valve of a patient, the support structure defining asupport-structure interior. An expandable prosthetic heart valve isdelivered into the native heart valve and into the support-structureinterior. The expandable prosthetic heart valve can be expanded whilethe expandable prosthetic heart valve is in the support-structureinterior and while the support structure is at the position on oradjacent to the surface of the outflow side of the native heart valve,thereby causing one or more native leaflets of the native heart valve tobe frictionally secured between the support structure and the expandedprosthetic heart valve. The expandable prosthetic heart valve can bedelivered from the inflow or the outflow side of the native heart valve.In certain embodiments, the native heart valve is an aortic valve, andthe act of delivering the expandable prosthetic heart valve comprisesdelivering the prosthetic heart valve through the left ventricle of thepatient's heart. In other embodiments, the native heart valve is anaortic valve, and the act of delivering the expandable prosthetic heartvalve comprises delivering the prosthetic heart valve through thepatient's aorta. In particular embodiments, the native heart valve is anaortic valve, the support structure is a support stent, and the act ofdelivering the support structure comprises advancing a first catheterthrough the aortic arch of the patient so that a distal end of the firstcatheter is near the aortic valve of the patient (the first catheter atleast partially enclosing a stent-delivery catheter, an inner catheter,and the support stent in a compressed state) and advancing thestent-delivery catheter and the inner catheter through the firstcatheter, thereby causing the support stent to be deployed from thedistal end of the first catheter and to expand into a decompressedstate. In other particular embodiments, the native heart valve is amitral valve, the support structure is a support band, and the act ofdelivering the support structure comprises advancing a first loopdelivery catheter into the left ventricle of the patient so that a firstdistal end of the first loop delivery catheter extends around a firstportion of the chordae tendineae, advancing a second loop deliverycatheter into the left ventricle of the patient so that a second distalend of the second loop delivery catheter extends around a second portionof the chordae tendineae and so that the second distal end of the secondloop delivery is adjacent to the first distal end of the first loopdelivery catheter, advancing a support band material through an interiorof the first loop delivery catheter and an interior of the second loopdelivery catheter, attaching a locking member to portions of the supportband material, and advancing the locking member along the portions ofthe support band material and into the left ventricle of the patient,thereby forming the support band around the chordae tendineae. Incertain embodiments, the act of delivering the support structurecomprises guiding the support structure to the position on or adjacentto the surface of the outflow side of the native heart valve and into adesired orientation, wherein the desired orientation aligns peaks of thesupport structure with either the tips or the commissures of the one ormore native leaflets. In further embodiments, the support structure isdisconnected from at least a delivery catheter once the one or morenative leaflets of the native heart valve are frictionally securedbetween the support structure and the expanded prosthetic heart valve.The disconnecting can be performed by retracting an inner catheterrelative to a stent-delivery catheter, thereby retracting inner prongscoupled to the inner catheter from corresponding apertures in retainingarms of the support stent. Alternatively, the disconnecting can beperformed by cutting through material used to form the supportstructure, thereby releasing the support structure from a catheter. Incertain embodiments, the act of expanding the expandable prostheticheart valve comprises inflating a balloon of a balloon catheter, theexpandable prosthetic heart valve being disposed around the balloon ofthe balloon catheter.

In other exemplary methods disclosed herein, a guide catheter isadvanced through the aortic arch of a patient so that a distal end ofthe guide catheter is near the aortic valve of the patient. In theseembodiments, the guide catheter at least partially encloses astent-delivery catheter and a compressed support stent releasablyconnected to the stent-delivery catheter. The stent-delivery catheter isadvanced through the guide catheter, thereby causing the support stentto be deployed from the distal end of the guide catheter and to becomeuncompressed. The uncompressed support stent is positioned adjacent toor on a surface of the aortic side of the aortic valve such that theleaflets of the aortic valve are circumscribed by the uncompressedsupport stent. The uncompressed support stent can then be disconnectedfrom the stent-delivery catheter. In certain embodiments, to disconnectthe support stent from the stent-delivery catheter, an inner catheterpositioned in the interior of the stent-delivery catheter can beretracted, causing an inner prong attached to the inner catheter towithdraw from an aperture associated with the support stent, and/or atleast one prong attached to the stent-delivery catheter can bedisconnected from the support stent.

Other exemplary embodiments disclosed herein include apparatus forsecuring a prosthetic valve to a native heart valve. For example,certain embodiments comprise a support stent having an annular body thatdefines one or more peaks and one or more valleys along itscircumference. The support stent can be radially compressible and selfexpandable. The support stent can be sized such that it can bepositioned within the aorta of a patient at a location adjacent to theaortic valve and thereby circumscribe the aortic valve. The supportstent can further comprise at least one retaining arm comprises anaperture at or near a respective one of the peaks. In particularembodiments, the support stent is formed from a single annular member.In some embodiments, the support stent consists of three peaks and threevalleys. The shape formed by the three peaks and the three valleys canapproximate the shape of the leaflets of the aortic valve when theaortic valve is fully opened. In certain embodiments, a projection ofthe annular body onto a first plane is ring shaped or starfish shaped,and the annular body defines the one or more peaks and the one or morevalleys in a direction perpendicular to the first plane. For example,the annular body can be sinusoidal or saw-tooth shaped along itscircumference. Certain embodiments further comprise a stent deliverycatheter having an outer fork that includes one or more outer prongs. Atleast one of the outer prongs can comprise an aperture that is sized toreceive at least a portion of one of the retaining arms of the supportstent. An inner catheter can be positioned in an interior of thestent-delivery catheter and have an inner fork. The inner fork cancomprise one or more inner prongs, and at least one of the inner prongscan be insertable through the aperture of the one of the retaining armswhen the one of the retaining arms has been at least partially insertedthrough the aperture of a respective one of the outer prongs.

Other exemplary embodiments disclosed herein are systems for deliveringa support frame for securing a prosthetic valve in a patient's nativeheart valve. Exemplary embodiments of the system comprise a guidecatheter, a frame-delivery catheter positioned in the interior of theguide catheter, an inner catheter positioned in the interior of theframe-delivery catheter, and an expandable support frame positioned inthe interior of the guide catheter in a radially compressed state. Adistal end of the frame-delivery catheter can have an outer fork portionthat comprises a plurality of flexible outer prongs. A distal end of theinner catheter can have an inner fork portion that comprises a pluralityof flexible inner prongs. The expandable support frame can comprise aplurality of retaining arms, which can be releasably connected tocorresponding ones of the outer prongs of the outer fork portion andcorresponding ones of the inner prongs of the inner fork portion. Theexpandable support frame can be generally annular and comprise shapedportions configured to frictionally secure native leaflets of apatient's heart valve against an exterior surface of a prosthetic valvewhen the patient's heart valve has been replaced by the prostheticvalve. Alternatively, the expandable support frame can comprise a mainbody and a U-shaped lip that surrounds a bottom region of the supportframe, the U-shaped lip having a diameter that is greater than adiameter of the main body. In particular embodiments, the guidecatheter, frame-delivery catheter, and the inner catheter are axiallyslidable relative to one another. In some embodiments, the retainingarms of the expandable support frame comprise respective retaining armapertures through which the corresponding ones of the inner prongs areinserted. The corresponding ones of the outer prongs can comprise, forexample, respective outer prong apertures through which the respectiveretaining arms are inserted. In certain embodiments, the correspondingones of the outer prongs and the corresponding ones of the inner prongsof the inner fork portion are configured such that relative retractionof either the corresponding ones of the inner prongs or thecorresponding ones of the outer prongs causes release of the respectiveretaining arms.

Another disclosed embodiment is an apparatus comprising a support stenthaving an annular main body portion and a generally U-shaped rim portionat one end of the main body portion. The support stent of thisembodiment is radially compressible into a compressed state and selfexpandable into an uncompressed state. Furthermore, the rim portion hasa diameter that is greater than a diameter of the annular main bodyportion and that is sized so that an outer perimeter of the rim portionwill engage the walls surrounding the aortic valve of a patient when thesupport stent is positioned within the aorta of the patient at alocation adjacent to the aortic valve. In some embodiments, the supportstent is made of a shape-memory alloy. In certain embodiments, theannular main body portion is sinusoidal or saw-tooth shaped along itscircumference. In some embodiments, the rim portion is located around abottom region of the main body portion. In certain embodiments, thesupport stent is made of multiple elements forming a criss-crosspattern. In particular embodiments, the apparatus further comprises atleast one retaining arm at or near a top region of the main bodyportion.

In another disclosed embodiment, a distal end of a first deliverycatheter is advanced into the left ventricle of a patient so that adistal portion of the first delivery catheter substantiallycircumscribes a first half of the patient's chordae tendineae. A distalend of a second delivery catheter is advanced into the left ventricle ofthe patient so that a distal portion of the second delivery cathetersubstantially circumscribes a second half of the patient's chordaetendineae and so that a distal end of the second delivery cathetercontacts a distal end of the first delivery catheter, thereby forming adelivery catheter junction. A support band material is advanced throughone of the first delivery catheter or the second delivery catheter,across the delivery catheter junction, and into the other one of thefirst delivery catheter or the second delivery catheter. The firstdelivery catheter and the second delivery catheter are retracted fromthe left ventricle of the patient. In certain embodiments, the distalend of the first delivery catheter and the distal end of the seconddelivery catheter are advanced through a puncture in the left ventricle.In other embodiments, the distal end of the first delivery catheter andthe distal end of the second delivery catheter are advanced through theaorta of the patient. In some embodiments, the distal end of the firstdelivery catheter magnetically engages the distal end of the seconddelivery catheter. In some embodiments, a first steerable sheath and asecond steerable sheath are advanced into the left ventricle. In theseembodiments, the act of advancing the distal end of the first deliverycatheter into the left ventricle comprises advancing the distal end ofthe first delivery catheter through an interior of the first steerablesheath, and the act of advancing the distal end of the second deliverycatheter into the left ventricle comprises advancing the distal end ofthe second delivery catheter through an interior of the second steerablesheath. In certain embodiments, an introducer sheath is advanced intothe left ventricle through a puncture in the left ventricle. In theseembodiments, the act of advancing the first steerable sheath and thesecond steerable sheath into the left ventricle comprises advancing thefirst steerable sheath and the second steerable sheath through theintroducer sheath. In some embodiments, a locking member is attached toportions of the support band material and advanced over the portions ofthe support band material, thereby adjusting a diameter of a loop formedby the support band material and the locking member and surrounding thechordae tendineae. The act of advancing the locking member over theportions of the support band material can be performed using a pushertube. In some embodiments, the loop formed by the support band materialand the locking member can be positioned around the outflow side of themitral valve. An expandable prosthetic heart valve can be advanced intothe mitral valve and the interior of the loop formed by the support bandmaterial and the locking member while the prosthetic heart valve is in acompressed state. The expandable prosthetic heart valve can be expandedinto an uncompressed state, thereby causing one or more native leafletsof the mitral valve to be frictionally secured between the loop and theexpandable prosthetic heart valve. Portions of the support band materialthat do not form part of the loop can be severed, thereby releasing theloop.

In another disclosed embodiment, a partial loop is formed around thechordae tendineae of a patient's heart with a cord of biocompatiblematerial. A locking member is attached to portions of the cord ofbiocompatible material. The locking member is advanced toward thechordae tendineae along the portions of the cord of biocompatiblematerial, thereby decreasing a diameter of a loop formed by the cord ofbiocompatible material and the locking member. In certain embodiments,an expandable prosthetic heart valve is positioned into the interior ofthe patient's mitral valve, the loop formed by the cord of biocompatiblematerial and the locking member is positioned around an outflow side ofthe patient's mitral valve so that the native leaflets of the mitralvalve open into the interior of the loop, and the expandable prostheticheart valve is expanded, thereby causing an exterior surface of theexpandable prosthetic heart valve to urge the native leaflets of themitral valve against an interior surface of the loop and to frictionallysecure the expandable prosthetic heart valve to the native leaflets ofthe mitral valve. In some embodiments, portions of the cord ofbiocompatible material are cut in order to release the loop formed bythe cord of biocompatible material and the locking member. In certainembodiments, an expandable prosthetic heart valve is advanced into theinterior of the patient's mitral valve and expanded. The exterior of theexpandable prosthetic heart valve can comprise one or more fasteningmechanisms configured to engage the native leaflets of the mitral valveand at least temporarily secure the expandable prosthetic heart to thenative leaflets. In certain implementations of these embodiments, theloop formed by the cord of biocompatible material and the locking memberis positioned around an outflow side of the patient's mitral valve sothat the loop circumscribes the native leaflets of the mitral valve andthe expanded prosthetic heart valve. In these embodiments, the act ofadvancing the locking member can decrease the diameter of the loopformed by the cord of biocompatible material and the locking member to adiameter that causes the expanded prosthetic heart valve to befrictionally secured to the native leaflets of the mitral valve. Incertain particular embodiments, the locking member is locked at adesired position along the portions of the support band material,thereby forming a support band having a substantially fixed diameter. Insome embodiments, the locking member can be unlocked, and the locationof the locking member adjusted along the portions of the support bandmaterial. In certain embodiments, the act of forming the partial looparound the chordae tendineae of the patient's heart is performed usingone or more delivery catheters inserted through the aortic arch of thepatient. In other embodiments, the act of forming the partial looparound the chordae tendineae of the patient's heart is performed usingone or more delivery catheters inserted through a puncture in the leftventricle of the patient.

Another disclosed embodiment is a system that comprises a first deliverycatheter having a first distal end region and a first distal end, asecond delivery catheter having a second distal end region and a seconddistal end, and an introducer sheath defining an interior that isconfigured to receive the first delivery catheter and the seconddelivery catheter. In these embodiments, the first distal end region issteerable into a first semi-circular shape, the second distal end regionis steerable into a second semi-circular shape, the first distal end hasa first magnetic polarity, and the second distal end has a secondmagnetic polarity opposite the first magnetic polarity. In certainembodiments, the introducer sheath is rigid and is sized for insertionthrough a puncture in the left ventricle of a patient. In otherembodiments, the introducer sheath is bendable and is sized forinsertion into the aortic arch of a patient. In some embodiments, thesystem further comprises a first catheter delivery sheath and a secondcatheter delivery sheath. In these embodiments, the first catheterdelivery sheath defines a first interior configured to receive the firstdelivery catheter and has a first distal sheath region that naturallyassumes a first arced shape. Further, the second catheter deliverysheath defines a second interior configured to receive the seconddelivery catheter and has a second distal sheath region that naturallyassumes a second arced shape. In these embodiments, the interior of theintroducer sheath is further configured to receive the first catheterdelivery sheath, the second catheter delivery sheath, the first deliverycatheter, and the second delivery catheter. In certain embodiments, thefirst catheter delivery sheath and the second catheter delivery sheathare manufactured at least in part from a shape-memory alloy.

Another disclosed embodiment is a system comprising a pusher tubedefining a first pusher tube lumen and a second pusher tube lumen and alocking member defining a first locking member lumen and a secondlocking member lumen. In these embodiments, the first and second pushertube lumens are sized to receive respective portions of a cord ofmaterial, and the first and second locking member lumens are also sizedto receive the respective portions of the cord and are furtherconfigured to allow movement of the locking member in a first directionalong the respective portions of the cord when pushed by the pusher tubebut prevent movement of the locking member in a second directionopposite the first direction along the respective portions of the cord.In certain embodiments, the pusher tube further comprises a rotatablecutting element located at a distal end of the pusher tube, therotatable cutting element being controllable from a proximal region ofthe pusher tube. In some embodiments, the first locking member lumen andthe second locking member lumen each comprise one or more angled collarsor teeth. In certain embodiments, the system further comprises anintroducer sheath having an introducer sheath interior through which thepusher tube and the locking member are advanceable. In some embodiments,the system further comprises a prosthetic-heart-valve-delivery catheter.In these embodiments, the introducer sheath interior is furtherconfigured to simultaneously receive the pusher tube and theprosthetic-heart-valve-delivery catheter.

Another disclosed embodiment is a system comprising a locking memberconfigured to receive two portions of a cord of biocompatible materialand to secure the two portions in a desired position relative to oneanother, an adjustment tool configured to position the locking memberinto the desired position and to engage a locking mechanism in thelocking member that secures the locking member to the two portions atthe desired position, a balloon catheter on which an expandableprosthetic heart valve is disposed, and an introducer sheath defining aninterior in which the adjustment tool and the balloon catheter can besimultaneously located. In certain embodiments, the adjustment tool isfurther configured to disengage the locking mechanism in the lockingmember, thereby unlocking the locking member from the two portions ofthe cord. In particular embodiments, the locking member comprises a pinmember and a ring member. The pin member can have a first end, a secondend, and openings for receiving the two portions of the cord, and thering member can have openings for receiving the two portions of the cordand be configured to receive at least a portion of the first end of thepin member. In some embodiments, the adjustment tool comprises a forkmember positioned at a distal end of the adjustment tool, an inner pushmember, and an outer push member. In these embodiments, the inner pushmember can be contained within a lumen of the adjustment tool and theouter push member can have a greater diameter than the inner push memberand surround at least a portion of the inner push member.

Another disclosed embodiment comprises a support band having an annularbody that defines a support band interior. The support band of thisembodiment is formed from a biocompatible material having a first endthat is secured to an opposite second end via a locking mechanism. Thesupport band of this embodiment is sized such that it can be positionedadjacent to the outflow side of the mitral valve of a patient andthereby circumscribe the native leaflets of the mitral valve. Moreover,the support band interior has a fixed diameter when the first end issecured to the second end such that when an expandable prosthetic heartvalve is expanded within the mitral valve and within the support bandinterior, the native leaflets of the mitral valve become pinched betweenthe expandable prosthetic heart valve and the support band, therebyfrictionally securing the expandable prosthetic heart valve to themitral valve. In certain embodiments, the first end of the support bandhas a larger diameter than the second end, and the first end of thesupport band defines an interior into which the second end can beinserted and secured by the locking mechanism. In some embodiments, thelocking mechanism comprises a snap-fit connection formed between thefirst end and the second end of the support band. In certainembodiments, the locking mechanism comprises a locking member having afirst lumen configured to receive the first end of the support band anda second lumen configured to receive the second end of the support band,the first lumen and the second lumen each comprising one or more angledteeth or collars that allow movement of the locking mechanism along thesupport band in only a single direction. In some embodiments, thelocking mechanism comprises a multi-element mechanism that can beselectively locked to and unlocked from the first end and the second endof the support band. In certain embodiments, one or more clamps arepositioned on the support band.

In another disclosed embodiment, a prosthetic heart valve is deliveredinto an interior of a native heart valve and expanded. A support band isdelivered to a position on or adjacent to the surface of the outflowside of the native heart valve such that an interior of the support bandsurrounds at least a portion of the prosthetic heart valve and at leasta portion of one or more native leaflets of the native heart valve. Thediameter of the support band is adjusted until the one or more nativeleaflets of the native heart valve are frictionally secured between thesupport band and the prosthetic heart valve. The prosthetic heart valvecan be an expandable prosthetic heart valve and expanded once it isdelivered into the interior of the native heart valve. The support bandcan be formed from a shape-memory metal or cord of support band materialand an adjustable locking member through which portions of the cordextend. During delivery of the support band, the support band can bedisconnected from at least a delivery catheter once the one or morenative leaflets of the native heart valve are frictionally securedbetween the support band and the prosthetic heart valve (e.g., bycutting through material used to form the support band).

The foregoing and other objects, features, and advantages of thedisclosed technology will become more apparent from the followingdetailed description, which proceeds with reference to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary embodiment of a supportstructure according to the disclosed technology.

FIG. 2 is a cross-sectional view of a native aortic valve with thesupport structure of FIG. 1 positioned therein.

FIGS. 3 and 4 are perspective views of an exemplary delivery system forthe support structure of FIG. 1. In particular, FIG. 3 shows thedelivery system before the support structure is deployed, and FIG. 4shows the delivery system after the support structure is deployed.

FIG. 5 is an exploded view of the components of the exemplary deliverysystem shown in FIGS. 3 and 4.

FIG. 6 is a zoomed-in perspective view showing the mechanism forreleasably connecting the support structure to the exemplary deliverysystem of FIGS. 3 and 4.

FIGS. 7 and 8 are cross-sectional views of a patient's heartillustrating how the delivery system of FIGS. 3 and 4 can operate todeploy the support structure of FIG. 1 to a desired position on thepatient's aortic valve.

FIGS. 9-13 are cross-sectional views of a patient's heart illustratinghow an exemplary transcatheter heart valve (“THV”) can be deployed tothe patient's aortic valve and frictionally secured to the nativeleaflets using the support structure of FIG. 1.

FIG. 14 is a perspective view of another exemplary embodiment of asupport structure according to the disclosed technology.

FIG. 15 is a top view of the support structure embodiment shown in FIG.14

FIG. 16 is a side view of the support structure embodiment shown in FIG.14.

FIG. 17 is a cross-sectional view of a patient's heart illustrating howa delivery system can operate to deploy the support structure of FIG. 14to a desired position on the patient's aortic valve.

FIG. 18 is a cross-sectional view of a patient's heart illustrating howan exemplary THV can be deployed through the aortic arch and into thepatient's aortic valve, where it can be frictionally secured to thenative leaflets using the support structure of FIG. 14.

FIGS. 19-27 are cross-sectional view of a patient's heart illustratinghow an exemplary support band can be deployed around the native leafletsof a patient's mitral valve and used to secure a THV to the nativeleaflets of the mitral valve. In FIGS. 19-27, the support band isdeployed using a transapical approach.

FIG. 28 is a cross-sectional view of a patient's heart illustrating howan exemplary support band as in FIGS. 19-27 can be deployed through theaortic arch.

FIG. 29 is a top view of an exemplary locking member that can be used tosecure portions of a cord of support band material to one another andthereby form a loop.

FIG. 30 is a top view of another exemplary locking member that can beused to secure portions of a cord of support band material to oneanother and thereby form a loop.

FIG. 31 is a perspective view of an exemplary adjustment tool (or pushertube) that can be used in connection with the locking member of FIG. 30.

FIG. 32 is a cross-sectional side view of the exemplary locking memberof FIG. 30.

FIG. 33 is a cross-sectional side view of the exemplary adjustment toolof FIG. 31.

FIGS. 34-37 are cross-sectional views illustrating how the exemplaryadjustment tool of FIG. 31 can be used to adjust, lock, and unlock theexemplary locking member of FIG. 30.

FIG. 38 is a cross-sectional perspective view of another exemplarylocking member that can be used to secure portions of a cord of supportband material to one another and thereby form a loop.

FIG. 39 is a cross-sectional perspective view of an exemplary pushertube that can be used in connection with the exemplary locking member ofFIG. 38.

DETAILED DESCRIPTION General Considerations

Disclosed below are representative embodiments of a support structure(sometimes referred to as a “support stent,” “support frame,” “supportband,” or “support loop”) that can be used to secure a prosthetic heartvalve within a native heart valve. For illustrative purposes,embodiments of the support structure are described as being used tosecure a transcatheter heart valve (“THV”) in the aortic valve or themitral valve of a heart. It should be understood that the disclosedsupport structure and THV can be configured for use with any other heartvalve as well. Also disclosed herein are exemplary methods and systemsfor deploying the support structure and corresponding THV. Although theexemplary methods and systems are mainly described in connection withreplacing an aortic or mitral valve, it should be understood that thedisclosed methods and systems can be adapted to deliver a supportstructure and THV to any heart valve.

For illustrative purposes, certain embodiments of the support structureare described as being used in connection with embodiments of theballoon-expandable THV described in U.S. Patent Application PublicationNo. 2007/0112422 (U.S. application Ser. No. 11/280,063), which is herebyexpressly incorporated herein by reference. It should be understood,however, that this particular usage is for illustrative purposes onlyand should not be construed as limiting. Instead, embodiments of thedisclosed support structure can be used to secure a wide variety of THVsdelivered through a variety of mechanisms (e.g., self-expanding heartvalves, other balloon-expanding heart valves, and the like). Forinstance, any of the embodiments described in U.S. Pat. No. 6,730,118can be used with embodiments of the disclosed support structure. U.S.Pat. No. 6,730,118 is hereby expressly incorporated herein by reference.

The described methods, systems, and apparatus should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The disclosed methods, systems, and apparatus are notlimited to any specific aspect, feature, or combination thereof, nor dothe disclosed methods, systems, and apparatus require that any one ormore specific advantages be present or problems be solved.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language set forthbelow. For example, operations described sequentially may in some casesbe rearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods, systems, and apparatus can be used in conjunctionwith other systems, methods, and apparatus.

Exemplary Embodiments for Replacing Aortic Valves

FIG. 1 is a perspective view showing an exemplary embodiment of asupport stent or frame 10. Support stent 10 has a generally annular ortorroidal body formed from a suitable shape-memory metal or alloy, suchas spring steel, Elgiloy®, or Nitinol. Desirably, the material fromwhich the support stent 10 is fabricated allows the support stent toautomatically expand to its functional size and shape when deployed butalso allows the support stent to be radially compressed to a smallerprofile for delivery through the patient's vasculature. In otherembodiments, however, the stent is not self expanding. In theseembodiments, and as more fully explained below, other mechanisms forexpanding the stent can be used (e.g., a balloon catheter).

In the illustrated embodiment, the projection of the support stent 10onto an x-y plane has a generally annular or torroidal shape. Theillustrated support stent 10 further defines a number of peaks andvalleys (or crests and troughs) along its circumference. For example,the support stent 10 is sinusoidally shaped in the z direction. In otherembodiments, the support stent 10 is shaped differently in the zdirection (e.g., sawtooth-shaped, ringlet-shaped, square-wave shaped, orotherwise shaped to include peaks and valleys).

The illustrated support stent 10 includes three peaks 20, 22, 24 andthree valleys 30, 32, 34. In the illustrated embodiment, the peaks 20,22, 24 are positioned above the valleys 30, 32, 34 in the z direction.In some embodiments, the peaks have greater radii than the valleys 30,32, 34, or vice versa. For instance, in some embodiments, the projectionof the support stent 10 onto an x-y plane forms a closed shape having avariable radius (e.g., a starfish shape).

The size of the support stent 10 can vary from implementation toimplementation. In particular embodiments, the support stent 10 is sizedsuch that the support stent can be positioned within the aorta of apatient at a location adjacent to the aortic valve, therebycircumscribing the aortic valve. Furthermore, in order to frictionallysecure a prosthetic heart valve in its interior, certain embodiments ofthe support stent 10 have a diameter that is equal to or smaller thanthe diameter of the prosthetic heart valve when fully expanded. Inparticular embodiments, for instance, the support stent can have aninner or outer diameter between 10 and 50 mm (e.g., between 17 and 28mm) and a height between 5 and 35 mm (e.g., between 8 and 18 mm).Furthermore, the thickness of the annular body of the support stent 10may vary from embodiment to embodiment, but in certain embodiments isbetween 0.3 and 1.2 mm.

FIG. 2 is a perspective view of the exemplary support stent 10positioned on the surface of an outflow side of a native aortic valveand further illustrates the shape of the support stent. In particular,it can be seen from FIG. 2 that the valleys 30, 32, 34 of the supportstent 10 are shaped so that they can be placed adjacent to commissures50, 52, 54 of the native leaflets 60, 62, 64 of the aortic valve.Furthermore, in the illustrated embodiment, the peaks 20, 22, 24 areshaped so that they generally approximate or minor the size and shape ofthe leaflets 60, 62, 64 but are slightly smaller and lower than theheight of the leaflets 60, 62, 64 at their tips when the aortic valve isfully opened. In other embodiments, the peaks 20, 22, 24 are oriented sothat they are adjacent to the commissures 50, 52, 54 of the nativeleaflets 60, 62, 64 and the valleys are opposite the apexes of theleaflets 60, 62, 64. The support stent 10 can be positioned in any otherorientation within the aortic valve as well.

It should be understood that the shape of the support stent or frame 10can vary from implementation to implementation. For example, in someembodiments, the support stent is not sinusoidal or otherwise shaped inthe z-plane. In other embodiments, the support stent is shaped as acylindrical band or sleeve. In general, the support stent or frame canbe any shape that defines an interior through which a THV can beinserted, thereby causing the native leaflets of the aortic valve (orother heart valve) to be pinched or securely held between the supportstent and the THV. Furthermore, the support stent can have a morecomplex structure. For example, although the support stent illustratedin FIGS. 1 and 2 is formed from a single annular member (or strut), thesupport stent can comprise multiple annular elements that interlock orare otherwise connected to one another (e.g., via multiple longitudinalmembers).

Returning to FIG. 1, the illustrated support stent 10 also includeretaining arms 21, 23, 25 that can be used to help position and deploythe support stent 10 into its proper location relative to the nativeaortic valve. The retaining arms 21, 23, 25 can have respectiveapertures 26, 27, 28. An exemplary deployment system and procedure fordeploying the support stent 10 using the retaining arms 21, 23, 25 aredescribed in more detail below. The support stent 10 can also have oneor more barbs located on its surface. Such barbs allow the support stent10 to be more securely affixed to the tissue surrounding the stent orthe leaflets of the aorta.

FIGS. 3 and 4 are side views of the distal end portion of an exemplarydelivery apparatus 100 for delivering the support stent 10 to itslocation adjacent the native aortic valve through a patient'svasculature. In particular, FIG. 3 shows the delivery apparatus when thesupport stent 10 is in a compressed, predeployed state, whereas FIG. 4shows the delivery apparatus when the support stent 10 is in adecompressed, deployed state. The delivery apparatus 100 comprises aguide catheter 102 having an elongated shaft 104, whose distal end 105is open in the illustrated embodiment. In other embodiments, the distalend 105 of the guide catheter 102 can be tapered into a conical shapecomprising multiple “flaps” forming a protective nose cone that can beurged apart when the support stent 10 and any interior catheters areadvanced therethrough. Furthermore, for illustrative purposes, the guidecatheter 102 is shown as being partially cut away, thus revealing thecatheters in its interior.

A proximal end (not shown) of the guide catheter 102 is connected to ahandle of the delivery apparatus 100. During delivery of a supportstent, the handle can be used by a surgeon to advance and retract thedelivery apparatus through the patient's vasculature. In a particularuse, the delivery apparatus 100 is advanced through the aortic arch of apatient's heart in the retrograde direction after having beenpercutaneously inserted through the femoral artery. The guide cathetercan be configured to be selectively steerable or bendable to facilitateadvancement of the delivery system 100 through the patient'svasculature. An exemplary steerable guide catheter as can be used inembodiments of the disclosed technology is described in detail in U.S.Patent Application Publication No. 2007/0005131 (U.S. patent applicationSer. No. 11/152,288), which is hereby expressly incorporated herein byreference.

The delivery apparatus 100 also includes a stent delivery catheter 108positioned in the interior of the guide catheter 102. The stent deliverycatheter 108 has an elongated shaft 110 and an outer fork 140 connectedto a distal end portion of the shaft 110. The shaft 110 of the stentdelivery catheter 108 can be configured to be moveable axially relativeto the shaft 104 of the guide catheter 102. Furthermore, the shaft 110of the stent delivery catheter 108 can be sized so that its exteriorwall is adjacent to or in contact with the inner wall of the shaft 104of the guide catheter 102.

The delivery apparatus 100 can also include an inner catheter 118positioned in the interior of the stent deliver catheter 108. The innercatheter 118 can have an elongated shaft 120 and an inner fork 138secured to the distal end portion of the shaft 120. The shaft 120 of theinner catheter 118 can be configured to be moveable axially relative tothe shaft 104 of the guide catheter 102 and relative to the shaft 110 ofthe stent delivery catheter 108. Furthermore, the shaft 120 of the innercatheter 118 can be sized so that its exterior wall is adjacent to or incontact with the inner wall of the shaft 110 of the stent deliverycatheter 108. A guide wire (not shown) can be inserted into the interiorof the inner catheter 118. The guide wire can be used, for example, tohelp ensure proper advancement of the guide catheter 102 and itsinterior catheters through the vasculature of a patient.

As best shown in FIG. 5, a stent retaining mechanism is formed from theinner fork 138 attached to the distal end portion of the shaft 120 ofthe inner catheter 118 and the outer fork 140 attached to the distal endportion of the shaft 110 of the stent delivery catheter 108. The innerfork 138 includes a plurality of flexible inner prongs 141, 142, 143(three in the illustrated embodiment) at is distal end corresponding tothe retaining arms 21, 23, 25 of the support stent 10, and a headportion 144 at its proximal end. The outer fork 140 includes a pluralityof flexible outer prongs 145, 146, 147 (three in the illustratedembodiment) at its distal end corresponding to the retaining arms 21,23, 25 of the stent 10, and a head portion 148 at its proximal end. Thedistal end portions of the outer prongs 145, 146, 147 are formed withrespective apertures 155, 156, 157 sized to receive the retaining arms21, 23, 25.

FIG. 6 is a zoomed-in view of one of the retaining arms 21, 23, 25 as itinterfaces with corresponding prongs of the outer fork 140 and the innerfork 138. In this example, retaining arm 21 is shown, though it shouldbe understood that the retaining mechanism is similarly formed for theretaining arms 23, 25. The distal end portion of the outer prong 145 isformed with the aperture 155. When assembled, the retaining arm 21 ofthe stent is inserted through the aperture 155 of the prong 145 of theouter fork and the prong 141 of the inner fork is inserted through theaperture 26 of the retaining arm 21 so as to retain the retaining arm 21in the aperture 155.

Retracting the inner prong 141 proximally (in the direction of arrow152) to remove the prong from the aperture 26 allows the retaining arm21 to be removed from the aperture 155, effectively releasing theretaining arm from the retaining mechanism. For instance, the outerprong 145 and the retaining arm 21 can be formed such that when theinner prong 141 is withdrawn from the aperture 26, the outer prong 145flexes radially inward (downward in FIG. 7) and/or the retaining arm 21of the support stent flexes radially outward (upward in FIG. 7), therebycausing the retaining arm 21 to be removed from the aperture 155. Inthis manner, the retaining mechanism formed by the inner fork 138 andthe outer fork 140 create a releasable connection with the support stent10 that is secure enough to retain the support stent to the stentdelivery catheter 108 and to allow the user to adjust the position ofthe support stent after it is deployed. When the support stent 10 ispositioned at the desired location adjacent to the leaflets of theaortic valve, the connection between the support stent and the retainingmechanism can be released by retracting the inner fork 138 relative tothe outer fork 140, as further described below. In other embodiments,the function of the inner fork and the outer fork can be reversed. Forexample, the prongs of the inner fork can be formed with apertures sizedto receive the corresponding retaining arms of the support stent and theprongs of the outer fork can be inserted through the apertures of theretaining arms when the retaining arms are placed through the aperturesof the prongs of the inner fork.

As best shown in the exploded view in FIG. 5, the head portion 144 ofthe inner fork can be connected to the distal end portion of the shaft120 of the inner catheter 118. In the illustrated embodiment, forexample, the head portion 144 of the inner fork is formed with aplurality of angularly spaced, inwardly biased retaining flanges 154. Anend piece of the shaft 120 can be formed as a cylindrical shaft havingan annular groove 121. On the distal side of the annular groove 121, theshaft 120 can have a collar 122 with an outer diameter that is slightlygreater than the diameter defined by the inner free ends of the flanges154. Thus, the inner fork 138 can be secured to the end piece byinserting head portion 144 of the inner fork onto the end piece of theshaft 120 until the flanges 154 flex inwardly into the annular groove121 adjacent the collar 122, thereby forming a snap-fit connectionbetween the head portion 144 and the shaft 120. The head portion 144 canhave a proximal end that engages an annular shoulder 123 of the shaft120 that is slightly larger in diameter so as to prevent the headportion from sliding longitudinally along the shaft 120 in the proximaldirection.

The head portion 148 of the outer fork can be secured to a distal endportion of the shaft 110 of the stent delivery catheter 108 in a similarmanner. As shown in FIG. 5, the head portion 148 can be formed with aplurality of angularly spaced, inwardly biased retaining flanges 155. Anend piece of the shaft 110 can be formed as a cylindrical shaft havingan annular groove 111. On the distal side of the annular groove 111, theshaft 110 can have a collar 112 with an outer diameter that is slightlygreater than the diameter defined by the free ends of the flanges 155.Thus, the outer fork 140 can be secured to the end piece of the shaft110 by inserting the shaft 110 onto the head portion 148 until theflanges flex inwardly into the groove 111, thereby forming a snap-fitconnection between the head portion 148 and the shaft 110. The headportion 148 can have a proximal end that engages an annular shoulder 123of the shaft 110 that is slightly larger so as to prevent the headportion from sliding longitudinally along the shaft 110 in the proximaldirection.

In FIG. 3, the support stent 10 is shown in a radially compressed statein the interior of the elongated shaft 104 of the guide catheter 102. Inthe radially compressed state, the distance along the z axis between apeak and an adjacent valley of the support stent is greater than thedistance along the z axis between the peak and the adjacent valley whenthe support stent is in it uncompressed state. The distal end portion ofthe shaft 104 can also be referred to as a delivery sheath for the stent10. In this undeployed and compressed state, the prongs of the outerfork 140 and the inner fork 138 of the stent delivery catheter 108 andthe inner catheter 118 engage the retaining arms 21, 23, 25 of thesupport stent 10 in the manner described above with respect to FIGS. 5and 6. To deploy the support stent 10 in the illustrated embodiment(advance the stent from the delivery system), the stent deliverycatheter 108 and the inner catheter 118 are advanced toward the distalend 105 of the guide catheter 102 using one or more control handles ormechanisms (not shown) located at the proximal end of the guide catheter102. This action causes the support stent 10 to be advanced outwardlythrough the distal end 105 of the guide catheter 102 and expand into itsrelaxed, uncompressed state (shown, for example, in FIGS. 1 and 2).

FIG. 4 is a perspective view showing the support stent 10 after it hasbeen advanced from the distal end of the guide catheter 102. As seen inFIG. 4, the support stent 10 now assumes its relaxed, uncompressed shapebut remains connected to the outer fork 140 and the inner fork 138 atits retaining arms 21, 23, 25. In this configuration, the support stent10 can be rotated (in the clockwise or counter-clockwise directions) orrepositioned (in the proximal and distal directions and/or into adifferent position in the x-y plane) into a proper orientation adjacentto its intended target area. For example, the support stent 10 can bepositioned against the upper surfaces of leaflets of the aortic valve inthe manner illustrated in FIG. 2 while the support stent 10 remainsconnected to the delivery system 100 via the retaining arms 21, 23, 25.As more fully illustrated below in FIGS. 7-12, a prosthetic valve (e.g.,a THV) can be delivered to the aortic valve through a transapicalapproach (e.g., through the apex of the heart and through the leftventricle) and deployed within the native valve such that the prostheticvalve is secured in place by frictional engagement between the supportstent, the native leaflets, and the prosthetic valve.

In particular embodiments, the support stent 10 is shaped so that theTHV can be positioned in the interior of the support stent along withthe native leaflets of the aortic valve. More specifically, the supportstent 10 can be shaped such that the native leaflets become trapped orpinched between the support stent 10 and the exterior of the THV whenthe THV is installed. For instance, the diameter of the support stent 10can be equal to or smaller than the maximum diameter of the THV whenfully expanded, thus causing the THV to be frictionally fit to theleaflets of the aortic valve and the support stent 10. This friction fitcreates a solid foundation for the THV that is independent of the stateor condition of the leaflets in the aortic valve. For example, THVs aremost commonly used for treating aortic stenosis, a condition in whichthe leaflets of the aortic valve become hardened with calcium. Thehardened leaflets typically provide a good support structure foranchoring the THV within the aortic annulus. Other conditions may exist,however, in which it is desirable to implant a THV into the aortic valveand which do not result in a hardening of the leaflets of the aorticvalve. For instance, the support stent 10 can be used as a foundationfor a THV when treating patients with aortic insufficiency. Aorticinsufficiency results when the aortic annulus dilates such that theaortic valve does not close tightly. With this condition, the aorticannulus is larger than normal and would otherwise require a large THV.Using a support stent or frame (such as the support stent or frame 10),however, a smaller THV can be used, thereby making the THV deliveryprocess easier and safer. Furthermore, the use of a support stentprotects against displacement of the THV if there is any furtherdilation of the aortic valve.

A support stent can be used to secure a THV in any situation in whichthe aorta or aortic valve may not be in condition to help support theTHV and is not limited to cases of aortic insufficiency. For example, asupport stent 10 can be used in cases in which the aortic annulus is toodilated or in which the leaflets of the aorta are too weak or soft. Thesupport stent can be used to create an anchor for the THV, for instance,in cases in which the native leaflet tissue is too soft because ofexcess collagen in the aorta.

FIGS. 7-13 illustrate one exemplary procedure for deploying the supportstent and securing a THV to the support stent. In particular, FIGS. 7-8are cross-sectional views through the left side of a patient's heartshowing the acts performed in delivering the support stent 10 throughthe aortic arch to the aortic valve. FIGS. 9-13 are cross-sectionalviews through the left side of a patient's heart showing the actsperformed in deploying a THV 250 and having it engage the support stent10. In order to better illustrate the components of the delivery system100, the guide catheter 102 is shown partially cut away in FIGS. 7-13.For the sake of brevity, certain details concerning the delivery systemof the THV 250 are omitted. Additional details and alternativeembodiments of the delivery system for the THV 250 that may be used withthe support stent described herein are discussed in U.S. PatentApplication Publication No. 2007/0112422 (U.S. application Ser. No.11/280,063), which is hereby expressly incorporated herein by reference.

FIG. 7 shows the guide catheter 102 of the delivery system 100 as it isadvanced through the aortic arch 202 into a position near the surface ofthe outflow side of the aortic valve 210. The delivery system 100 can beinserted through the femoral artery of the patient and advanced into theaorta in the retrograde direction. FIG. 7 also shows the stent deliverycatheter 108, the inner catheter 118, and the support stent 10. In FIG.7, the support stent 10 is in its radially compressed, predeploymentstate. Also seen in FIG. 7 are the outer fork 140 and the inner fork138, which couple the radially compressed support stent 10 to the distalends of the stent delivery catheter 108 and the inner catheter 118,respectively.

FIG. 8 shows the support stent 10 after it has been advanced through thedistal end of the guide catheter 102 and assumes its final, uncompressedshape in a position above and adjacent to the aortic valve 210. Thesupport stent 10 can also be placed directly on the surface of theoutflow side of the aortic valve. FIG. 8 shows that the stent deliverycatheter 108 and the inner catheter 118 have been advanced though thedistal end of the guide catheter 102, thereby pushing the support stent10 out of the guide catheter and allowing it to expand into its naturalshape. In particular embodiments, the support stent 10 is rotated andpositioned as necessary so that the support stent generallycircumscribes the aortic valve and so that the peaks of the supportstent are aligned with the tips of the natural leaflets of the aorticvalve 210. Therefore, when the THV is inserted and expanded within theaortic valve 210, the leaflets of the aortic valve will engage at leastthe majority of the surface in the interior of the support stent 10.This alignment will create an overall tighter fit between the supportstent 10 and the THV. In other embodiments, the support stent 10 isrotated and positioned as necessary so that the peaks of the supportstent 10 are aligned with the commissures or other portions of theaortic valve. The position of the guide catheter 102 and the supportstent 10 relative to the aortic valve 210, as well as the position ofother elements of the system, can be monitored using radiopaque markersand fluoroscopy, or using other imaging systems such as transesophagealecho, transthoracic echo, intravascular ultrasound imaging (“IVUS”), oran injectable dye that is radiopaque.

Also seen in FIG. 8 are the prongs of the outer fork 140 and the prongsof the inner fork 138. In the exemplary procedure, the prongs of theouter fork 140 and the inner fork 138 remain secured to the supportstent 10 until the THV is deployed and frictionally engaged to thesupport stent. The inner and outer forks desirably form a connectionbetween the stent 10 and the delivery system that is secure and rigidenough to allow the surgeon to hold the stent 10 at the desiredimplanted position against the flow of blood while the THV is beingimplanted.

In FIG. 8, the support stent 10 is self-expanding. In other embodiments,however, the support stent may not be self-expanding. In suchembodiments, the support stent can be made of a suitable ductilematerial, such as stainless steel. In addition, a mechanism forexpanding the support stent can be included as part of the deliverysystem 100. For example, the support stent can be disposed around aballoon of a balloon catheter in a compressed state. The ballooncatheter can have a shaft that is interior to the inner catheter 118.Because the stent 10 is not self-expanding, the distal end portion ofthe guide catheter 102 need not extend over the compressed supportstent. During delivery of the support stent, the support stent, ballooncatheter, inner catheter 118, and stent delivery catheter 108 can beadvanced from the distal end of the guide catheter 102. The balloonportion of the balloon catheter can be inflated, causing the supportstent to expand. The balloon portion can subsequently be deflated andthe balloon catheter withdrawn into the delivery system 100 to removethe balloon from the interior of the support stent while the supportstent remains connected to the inner catheter for positioning of thesupport stent. The delivery of the support stent otherwise proceeds asin the illustrated embodiment using the self-expanding support stent 10.

FIG. 9 shows an introducer sheath 220 passing into the left ventriclethrough a puncture 222 and over a guidewire 224 that extends upwardthrough the aortic valve 210. The surgeon locates a distal tip 221 ofthe introducer sheath 220 just to the inflow side of the aortic valve210. The position of the introducer sheath 220 relative to the aorticvalve 210, as well as the position of other elements of the system, canbe monitored using radiopaque markers and fluoroscopy, or using otherimaging systems.

FIG. 10 shows the advancement of the balloon catheter 230 over theguidewire 224 and through the introducer sheath 220. Ultimately, as seenin FIG. 11, the THV 250 is located at the aortic annulus and between thenative aortic leaflets. FIG. 11 also illustrates retraction of theintroducer sheath 220 from its more distal position in FIG. 10.Radiopaque markers may be provided on the distal end of the introducersheath 220 to more accurately determine its position relative to thevalve 210 and balloon 232. In order to better illustrate the componentsof the delivery system for the THV, FIGS. 10-11 do not show the frontthird of the support stent 10 or the corresponding outer and inner prongof the outer fork and the inner fork, respectively. Furthermore, forpurpose of illustrating the relative position of the support stent 10 onthe THV 250, FIGS. 12-13 show the front third of the support stent 10and the front of the THV 250, but do not show the portions of the nativeheart valve that would be secured by the front of the support stent 10.It is to be understood, however, that a corresponding leaflet of thenative heart valve would be secured between the support stent 10 and theTHV 250.

Again, the precise positioning of the THV 250 may be accomplished bylocating radiopaque markers on its distal and proximal ends. In someembodiments, the surgeon can adjust the position of the valve 250 byactuating a steering or deflecting mechanism within the balloon catheter230. Furthermore, the rotational orientation of the valve 250 can beadjusted relative to the cusps and commissures of the native aorticvalve by twisting the balloon catheter 230 from its proximal end andobserving specific markers on the valve (or balloon catheter) underfluoroscopy. One of the coronary ostia 280 opening into one of thesinuses of the ascending aorta is also shown in FIG. 11, and those ofskill in the art will understand that it is important not to occlude thetwo coronary ostia with the prosthetic valve 250.

FIG. 11 shows the THV 250 in its contracted or unexpanded state crimpedaround the balloon 232. When the surgeon is satisfied of the properpositioning and rotational orientation of the valve 250, the balloon 232is expanded to engage the support stent 10 as seen in FIG. 12. Theengagement of the support stent 10 to the exterior of the THV 250pinches the leaflets of the aortic valve between the support stent andthe THV 250, and thereby secures the THV within the annulus of theaortic valve. Once secured into this position, the inner catheter 118 ofthe delivery system 100 can be retracted, thereby causing the prongs ofthe inner fork 138 to become disengaged from the retaining arms of thesupport stent 10. Once the prongs of the inner fork 138 are disengaged,the prongs of the outer fork 140 can be disengaged from the retainingarms by retracting the stent delivery catheter 108. Once disengaged fromthe support stent, the delivery system 100 can be retracted from theaortic arch and removed from the patient.

It should be noted that the valve 250 can take a variety of differentforms and may comprise an expandable stent portion that supports a valvestructure. The stent portion desirably has sufficient radial strength tohold the valve at the treatment site and to securely engage the supportstent 10. Additional details regarding balloon expandable valveembodiments that can be used in connection with the disclosed technologyare described in U.S. Pat. Nos. 6,730,118 and 6,893,460, both of whichare hereby expressly incorporated herein by reference.

Once the valve 250 is properly implanted, as seen in FIG. 13, theballoon 232 is deflated, and the entire delivery system including theballoon catheter 230 is withdrawn over the guidewire 224. The guidewire224 can then be withdrawn, followed by the introducer sheath 220.Ultimately, purse-string sutures 260 at the left ventricular apex can becinched tight and tied to close the puncture.

FIGS. 14-16 shows another embodiment of a support stent or frame 310that can be used to help secure a THV into the interior of a nativeheart valve, such as the aortic valve. In particular, FIG. 14 is aperspective view of the support stent 310, FIG. 15 is a top view of thesupport stent 310, and FIG. 16 is a side view of the support stent 310.Like support stent 10, support stent 310 has a generally annular ortorroidal body formed from a suitable shape-memory metal or alloy, suchas spring steel, Elgiloy®, or Nitinol. The support stent 310 is alsoradially compressible to a smaller profile and can self expand whendeployed into its functional size and shape. In other embodiments,however, the support stent 310 is not self expanding.

The support stent 310 includes a generally cylindrical main body portion320 and a rim portion 330. The support stent 310 can be a meshstructure, which can be formed, for example, from multiple elements inwhich approximately half of the elements are angled in a first directionand approximately half of the elements are angled in a second direction,thereby creating a criss-cross or diamond-shaped pattern. In theillustrated embodiment, the rim portion 330 has a greater diameter thanthe main body portion 320 and is formed as an extension at a bottomregion of the main body portion that is folded outwardly from the mainbody portion and back toward a top region of the main body portion. Therim portion 330 thus forms a U-shaped rim or lip around the bottomregion of the support stent 310. In general, the rim portion 330 isdesigned to have a diameter that is slightly larger than the walls ofthe aortic arch that surround the aortic valve. Thus, when the supportstent 310 is delivered to the aortic valve and deployed at the aorta,the rim portion 330 expands to engage the surrounding aorta wall andfrictionally secures the support stent 310. At the same time, the mainbody portion 320 defines an interior into which an expandable THV can beexpanded and which further engages the native leaflets of the aorticvalve. Thus, the main body portion 320 operates in the same manner asthe support stent 10 described above and illustrated in FIGS. 1-12,whereas the rim portion 330 of the support stent 310 operates to securethe support stent in place by engaging the walls of the aorta thatsurround the aortic valve.

As best seen in FIGS. 14 and 16, the support stent 310 further includesretaining arms 321, 322, 323 that can be used to help position anddeploy the support stent 310 into its proper location relative to thenative aortic valve. The retaining arms 321, 322, 323 can haverespective apertures 326, 327, 328. In general, the retaining arms 321,322, 323 are constructed and function in a similar manner as retainingarms 21, 23, 25 described above in the embodiment illustrated in FIGS.1-12.

FIGS. 17-18 illustrate one exemplary procedure for deploying the supportstent 310 and securing a THV 340 within an interior of the supportstent. In particular, FIGS. 17-18 are cross-sectional views through theleft side of a patient's heart showing the acts performed in deliveringthe support stent 310 through the aortic arch to the aortic valve. Forthe sake of brevity, certain details concerning the delivery system ofthe THV 340 are omitted. Additional details and alternative embodimentsof the delivery system for the THV 340 that may be used with the supportstent described herein are discussed in U.S. Patent ApplicationPublication No. 2008/0065011 (U.S. application Ser. No. 11/852,977) andU.S. Patent Application Publication No. 2007/0005131 (U.S. applicationSer. No. 11/152,288), which are hereby expressly incorporated herein byreference.

FIG. 17 shows an outer catheter 352 (which can be a guide catheter) of adelivery system 350 as it is advanced through the aortic arch 302 into aposition near the surface of the outflow side of the aortic valve 304.The delivery system 350 can be inserted through the femoral artery ofthe patient and advanced into the aorta in the retrograde direction.FIG. 17 also shows a stent delivery catheter 354, an inner catheter 356,and the support stent 310. Also seen in FIG. 17 are the outer fork 360and the inner fork 362, which couple the support stent 310 to the distalends of the stent delivery catheter 354 and the inner catheter 356,respectively.

More specifically, FIG. 17 shows the support stent 310 after it has beenadvanced through the distal end of the guide catheter 352 and assumesits final, uncompressed shape in a position adjacent to the aortic valve304. In order to better illustrate the components of the delivery systemfor the THV, FIGS. 17-18 do not show the entire front side of thesupport stent 310 or the corresponding valve leaflet that would besecured by the front side of the support stent 310. It is to beunderstood, however, that in practice the entire support stent 310 wouldexist and engage a corresponding leaflet of the native heart valve.

The support stent 310 can be positioned adjacent to the aortic valve 304so that the rim portion 330 of the support stent engages the wallssurrounding the aortic valve 304 and exerts an outward force againstthose walls, thereby securing the support stent 310 within the aorta.This positioning can be achieved, for example, by advancing the guidecatheter 352 to a position directly adjacent the aortic valve 304 whilethe stent delivery catheter 354 and the inner catheter 356 areundeployed and while the support stent 310 remains in its compressedstate. The guide catheter 352 can then be retracted while the stentdelivery catheter 354 and the inner catheter 356 are held in place,thereby allowing the support stent 310 to expand toward its naturalshape. As with the delivery system 100 described above, the position ofthe guide catheter 352 and the support stent 310 relative to the aorticvalve 304, as well as the position of other elements of the system, canbe monitored using radiopaque markers and fluoroscopy, or using otherimaging systems such as transesophageal echo, transthoracic echo, IVUS,or an injectable dye that is radiopaque.

Once the support stent 310 is positioned into the desired locationadjacent the aortic valve 304, the prongs of the inner fork 362 can bedisengaged from the corresponding apertures of the retaining arms of thesupport stent 310. For example, the inner catheter 356 can be retractedinto the interior of the stent delivery catheter 354, thereby releasingthe support stent 310 from the outer fork 360 and the inner fork 362.The delivery system 350 can then be retracted from the aorta and removedfrom the patient's body.

With the support stent 310 secured to the aortic valve, a THV (such asany of the THVs discussed above) can be introduced. In contrast to theprocedure illustrated in FIGS. 7-13, a delivery system having a deliverycatheter that is advanced through the patient's aorta can be used todeliver the THV. In other words, a transfemoral approach can be used.For instance, any of the exemplary systems and methods described in U.S.Patent Application Publication No. 2008/0065011 (U.S. application Ser.No. 11/852,977) or U.S. Patent Application Publication No. 2007/0005131(U.S. application Ser. No. 11/152,288) can be used with the supportstent 310. Alternatively, the transapical approach shown in FIGS. 7-13can be used.

FIG. 18 shows delivery system 380 comprising an outer catheter 382(which can be a guide catheter) and a balloon catheter 390 extendingthrough the guide catheter. The balloon catheter 390 has a balloon atits distal end on which the THV is mounted. As with the delivery system350, the delivery system 380 can be inserted through the femoral arteryof the patient and advanced into the aorta in the retrograde direction.FIG. 18 further shows a guidewire 392 that has been first inserted intothe patient's vasculature and advanced into the left ventricle. Thedelivery system can then be inserted into the body and advanced over theguidewire 392 until the THV is positioned within the interior of theaortic valve. As shown, the THV is not only in the interior of theaortic valve 304 but also in the interior of the main body portion ofthe support stent 310.

FIG. 18 shows the THV 340 in its contracted (or unexpanded) statecrimped around the balloon portion of the balloon catheter 390. When thesurgeon is satisfied of the proper positioning, the balloon of theballoon catheter 390 can be expanded such that the THV 340 expands andurges the native leaflets of the aortic valve against the support stent310, thereby securing the THV within the annulus of the aortic valve.Once the THV 340 is properly implanted, the balloon of the ballooncatheter 390 is deflated, and the entire delivery system 380 includingthe balloon catheter is withdrawn over the guidewire 392. The guidewire392 can then be withdrawn.

Other methods of delivering a support stent and THV to the aortic valveor any other heart valve are also possible. For example, in certainembodiments, the support stent and the THV are delivered surgically tothe desired heart valve (e.g., in an open-heart surgical procedure).Furthermore, in certain embodiments in which the support stent and THVare delivered surgically, non-compressible support stents and/or THVsare used.

Exemplary Embodiments for Replacing Mitral Valves

The mitral valve can also suffer from valve insufficiency, which may bedesirably treated through the implantation of a prosthetic valve. Aswith aortic valve insufficiency, mitral valve insufficiency often causesthe valve annulus to be dilated and the valve leaflets to be too soft toprovide reliable support for securing a prosthetic valve. Accordingly,and according to certain exemplary embodiments of the disclosedtechnology, it is desirable to use a support structure to help secure atranscatheter heart valve (“THV”) within a patient's mitral valve. Aswith the support stents and frames described above, the mitral valvesupport structure is desirably positioned on the outflow side of themitral valve. The THV can be inserted into the interiors of the nativemitral valve and the support structure and then expanded such that themitral valve leaflets are frictionally engaged between the exteriorsurface of the THV and the interior surface of the support structure.Alternatively, the support structure can be deployed after the THV ispositioned and expanded within the mitral valve. The diameter of thesupport structure can then be adjusted such that the valve leaflets arefrictionally engaged against the exterior of the THV. By using a supportstructure to secure the THV, a smaller THV can be used, thereby makingthe THV delivery process easier and safer. Furthermore, the use of asupport structure protects against displacement of the THV if there isany further dilation of the aortic valve. Moreover, when a supportstructure is used to secure the THV, the native leaflets function as asealing ring around the valve that prevents paravalvular leaks.

The support structure for the mitral valve can have a variety of shapes.For example, in some embodiments, the support structure has a sinusoidalshape as with the support stent 110, but in other embodiments does nothave a sinusoidal shape or is not otherwise shaped in the z-plane. Infurther embodiments, the support stent is shaped as a cylindrical bandor sleeve. The support frame can also have a more complex structure. Ingeneral, any of the shapes and materials used for embodiments of theaortic valve support structures described above can be used forembodiments of the mitral valve support structures and vice versa.

In one exemplary embodiment, the mitral valve support structure is madeof a suitable biocompatible material that can be delivered through oneor more delivery catheters and formed into a band or loop. For thisreason, the structure is sometimes referred to herein as a “supportband” or “support loop.” The biocompatible material may comprise, forexample, nylon, silk, polyester, or other synthetic biocompatiblematerial. The biocompatible material may alternatively comprise anatural material, such as catgut. In still other embodiments, thesupport structure is formed of a biocompatible shape-memory metal oralloy, such as spring steel, Elgiloy®, or Nitinol.

FIGS. 19-27 show one exemplary procedure for delivering a supportstructure to the mitral valve and having it secure a THV into itsdesired position within the mitral valve. In particular, FIGS. 19-24 arecross-sectional views through the left side of a patient's heart showingthe acts performed in delivering the support structure using atransapical approach. FIGS. 25-27 are cross-sectional views through theleft side of a patient's heart showing the acts performed in deploying aTHV and having it engage the mitral valve leaflets and the interior ofthe support structure. It should be noted that FIGS. 19-27 are schematicin nature and thus do not necessarily depict a precise representation ofthe delivery process. For example, the patient's ribcage is not shownfor illustrative purposes and the size of the sheaths used with thedelivery system have been altered somewhat in order to better illustratethe procedure. One of ordinary skill in the art, however, will readilyunderstand the range and types of sheaths and catheters that can be usedto implement the depicted procedure.

FIG. 19 shows an introducer sheath 400 inserted into the left ventricleof a patient's heart through a puncture 402. In particularimplementations, the introducer sheath 400 is positioned so that it isnot directly centered about the outflow side of the mitral valve, butrather is offset from the center. In particular, the introducer sheath400 can be positioned so that it is on the exterior side of the spaceenclosed by chordae tendineae 412. It should be noted that in FIGS.19-27, the chordae tendineae 412 of the left ventricle are onlypartially shown. It is to be understood, however, that the chordaetendineae 412 are respectively attached to each of the mitral valveleaflets and to the papillary muscles of the left ventricle. A surgeoncan locate a distal tip 401 of the introducer sheath 400 near theoutflow side of the mitral valve (e.g., within 1-10 millimeters).

FIG. 20 shows a first catheter delivery sheath 420 and a second catheterdelivery sheath 422 being advanced through the interior of theintroducer sheath 400. The introducer sheath 400 can define two or moreseparate lumens through which the first and the second catheter deliverysheaths 420, 422 can be inserted or can define a single lumensufficiently large to receive both the first and the second catheterdelivery sheaths 420, 422. The first and second catheter deliverysheaths 420, 422 can be shaped so that they arc outwardly from eachother when advanced out of the distal tip 401 of the introducer sheath400. For example, in the illustrated embodiment, the first and secondcatheter delivery sheaths 420, 422 have end regions 421, 423 that archabout 90 degrees (or some other amount, such as between 45-90 degrees)when they are in their natural state. The amount of arching may varyfrom implementation to implementation but is desirably selected so thatthe tips of the end portions 421, 423 are in approximately the sameplane. In other embodiments, the catheter delivery sheaths 420, 422 arenot used as part of the support structure delivery procedure.

In FIG. 21, a first loop delivery catheter 430 is advanced through theinterior of the first catheter delivery sheath 420 and extendedsubstantially around the exterior of one half of the chordae tendineae(e.g., the medial half of the chordae tendineae). Similarly, a secondloop deliver catheter 432 is advanced through the interior of the secondcatheter delivery sheath 422 and extended substantially around theexterior of the other half of the chordae tendineae (e.g., the lateralhalf of the chordae tendineae). The loop delivery catheters 430, 432 canbe steerable catheters having end regions that can be selectivelydeformed or arched by an operator. Such steerable catheters are wellknown in the art. The loop delivery catheters 420, 432 can additionallybe magnetic or have magnetic distal end portions. For example, in theillustrated embodiment, the first loop delivery catheter 430 has amagnetic distal end portion 431 with a first polarity, and the secondloop delivery catheter 432 has a magnetic distal end portion 433 with asecond polarity opposite the first polarity. As a result of theirmagnetization, the end portions 431, 433 are attracted to one anotherand will form a contiguous junction when in sufficient proximity to eachother. Other mechanisms for engaging the end portions 431, 433 to oneanother are also possible (e.g., a hook mechanism, an adhesive, anenlarged diameter of one end portion, and other such mechanisms). Whenthe end portions 431, 433 are engaged to one another, the first and thesecond loop delivery catheters 430, 432 form a single interior or lumenthrough which a support band material can be advanced. Furthermore, whenthe end portions 431, 433 are engaged to one another, the first and thesecond loop delivery catheters 430, 432 create a partial loop thatcircumscribes the chordae tendineae.

FIG. 22 shows the magnetic distal end portions 431, 433 after the firstand second loop delivery catheters 430, 432 are arched around thechordae tendineae and after the distal end portions have beenmagnetically engaged to one another. In this configuration, a cord 440of biocompatible material can be advanced through the interior of one ofthe loop delivery catheters 430, 432 and into the interior of the otherone of the loop delivery catheters. As used herein, the term “cord”refers to a slender length of material that can be formed from a singlestrand, fiber, or filament, or can comprise multiple strands, fibers, orfilaments. In one particular implementation, an end 442 of the cord 440can be advanced from a proximal end of the first loop delivery catheter430, through the interior of the first loop delivery catheter, throughthe junction formed by the distal end portions 431, 433, and through theinterior of the second loop delivery catheter 432 until it appears onthe proximate end of the second loop delivery catheter 432. In oneparticular embodiment, the cord 440 is a guidewire (e.g., a guidewiremade of stainless steel or other suitable metal). The guidewire can thenbe attached to another cord of biocompatible material used to form thesupport band and pulled through the interior of the first and the secondloop delivery catheters 430, 432, thereby positioning the cord ofbiocompatible material around the chordae tendineae in a partial loop.With the cord of biocompatible material delivered around the chordaetendineae, the first and second loop delivery catheters 430, 432 and thefirst and second catheter delivery sheaths 420, 422 can be retractedfrom the introducer sheath 400.

FIG. 23 shows a cord 443 of biocompatible material used to form thesupport band positioned around the chordae tendineae after the first andsecond loop delivery catheters 430, 432 and the first and secondcatheter delivery sheaths 430, 422 have been withdrawn. In FIG. 23, asheath 450 is inserted over both ends of the cord 443 and over a firstportion 444 and a second portion 446 of the cord 443, which run throughthe length of the sheath 450.

As shown in FIG. 24, a locking member 460 can be advanced over the firstand second portions 444, 446 of the cord 443 and into the leftventricle. The locking member 460 can be advanced, for example, by apusher tube 462 that pushes the locking member 460 over the portions444, 446 of the cord 440. In one particular embodiment, the lockingmember 460 includes lumens or other openings configured to receive eachof the two portions 444, 446 and permits movement along the portions444, 446 in only a single direction. In certain other embodiments, thelocking member 460 can be unlocked from the portions 444, 446 of thecord 440 and advanced in both directions along the cord 440. In theillustrated embodiment, the pusher tube 462 is further configured tosever the portions of the cord 440 that extend through a proximal sideof the locking member 460, thereby releasing a support band 441 formedby the locking member 460 and the loop-shaped portion of the cord 443from the pusher tube 462. As more fully shown in FIG. 25, the pushertube 462 can further be formed of a shape memory material or include adeflection mechanism that allows the pusher tube to have an arched shapetoward its distal end. On account of this arched shape, the pusher tube462 can be used to better position the support band 441 formed by theloop-shaped portion of the cord 443 and the locking member 460 adjacentto the outflow side of the mitral valve such that the native leaflets ofthe mitral valve open into an interior of the support band 441.

As shown in FIG. 25, the sheath 450 can be withdrawn from the introducersheath 400 once the locking member 460 and the pusher tube 462 areadvanced into the left ventricle. A balloon catheter 470 can be advancedthrough the introducer sheath 400 and into the interior of the mitralvalve 410 of the patient. Although not shown in the illustratedembodiment, the balloon catheter may be guided by a guidewire into thecenter of the mitral valve. Ultimately, and as seen in FIG. 25, aballoon portion 472 of the balloon catheter 470 around which a THV 480is crimped can be located within the mitral annulus. Radiopaque markersor other imaging enhancers may be provided on the distal end of theintroducer sheath 400 and the balloon catheter 470 to more accuratelydetermine the position of the THV 480 relative to the native valve 410.In some embodiments, a surgeon can adjust the position of the THV 480 byactuating a steering or deflecting mechanism within the balloon catheter470.

As also shown in FIG. 25, the locking member 460 and the pusher tube 462can be positioned so as not to interfere with the balloon catheter 470.Furthermore, with the THV 480 properly positioned within the mitralvalve 410, the pusher tube 462 can be used to position the support band441 formed by the loop-shaped remaining portion of the cord 443 aroundthe native valve leaflets of the mitral valve. Radiopaque markers orother suitable imaging enhancers can be provided on the pusher tube 462,the locking member 460, and/or the loop-portion of the cord to allow forthe proper positioning of the support band 441 relative to the valveleaflets. With the THV 480 in its desired position, the balloon portion472 of the balloon catheter 470 can be inflated, thereby expanding theTHV 480 against the native valve leaflets and causing the leaflets tofrictionally engage the interior surface of the support band 441. Thisexpansion secures the THV 480 to the native valve leaflets. In otherwords, the expansion pinches the native leaflets of the mitral valvebetween the support band 441 and the THV 480, and thereby secures theTHV within the annulus of the mitral valve.

As shown in FIG. 26, with the THV 480 secured against the native mitralvalve leaflets and the support band 441, the balloon portion 472 of theballoon catheter 470 can be deflated and the balloon catheter withdrawnfrom the introducer sheath 400. The pusher tube 462 can then bedisengaged from the loop 441. For example, the pusher tube 462 cancomprise a cutting element at its distal end that can be activated bythe surgeon from the proximal end. An example of one suitable cuttingelement is shown below with respect to FIG. 39. Alternatively, aseparate cutting device (e.g., a cutting catheter or catheter having acontrollable cutting element) can be inserted through the introducersheath 400 and used to cut the portions of the cord 443 that extendthrough the proximal side of the locking member 460 and do not form partof the support band 441.

FIG. 27 shows the THV 480 secured within the native mitral valve afterthe support band 441 has been released from the pusher tube 462 and thepusher tube has been retracted from the introducer sheath 400. It shouldbe noted that the THV 480 can take a variety of different forms and maycomprise an expandable stent portion that supports a valve structure.The stent portion desirably has sufficient radial strength to hold thevalve at the treatment site and to securely engage the support band 441.

It will be understood by those of ordinary skill in the art that theabove-described loop deployment technique can be modified in a number ofmanners without departing from the disclosed technology. For example, insome embodiments, the THV is delivered and expanded into the mitralvalve before the support band is delivered to the left ventricle. Inthese embodiments, the THV can be temporarily secured within the mitralvalve. For example, the THV can be temporarily secured to the mitralvalve using one or more anchoring members on the exterior of the THV(e.g., anchoring members having a main body and one or more hook-shapedor umbrella-shaped barbs). The THV can also be temporarily securedwithin the mitral valve through the use of one or more spring-loadedclamps, rivets, clasps, or other such fastening mechanisms. With the THVtemporarily secured, the support band can be delivered around the nativeleaflets as described above and the diameter of the support band reduceduntil a desired frictional fit is created between the support band, theleaflets, and the THV. Any of the locking members described herein thatallow the diameter of the support band to be adjusted can be used toachieve the desired diameter.

Further, although the delivery method shown in FIGS. 19-27 uses atransapical approach, a delivery system adapted for introduction throughthe patient's aortic arch can alternatively be used. FIG. 28 shows anexample of such a delivery system 500. In particular, FIG. 28 shows thedelivery system 500 after a delivery catheter has been advanced throughthe aortic arch to a position adjacent the aortic valve and as a firstloop deliver catheter 510 and a second loop deliver catheter 512 aredeployed through the distal end of a delivery catheter 502. As with theprocedure described above, the first and second loop delivery catheters510, 512 can be steerable and comprise magnetic distal end portions thatallow the catheters 510, 512 to engage one another on a distal side ofthe chordae tendineae, thereby forming a delivery lumen through whichbiocompatible material for the support band or loop can be deployed.Also shown in FIG. 28 is an introducer sheath 520 and a balloon deliverycatheter 522 for deploying a THV 524. Besides the adaptations for aorticdelivery, the delivery procedure can otherwise be substantially similaror identical to the procedure shown in FIGS. 19-27.

Still other delivery variations are possible. For instance, the supportband may be formed of a shape-memory material that assumes a C-shapewhen not acted on by any external forces. The support band can befurther configured such that one end of the C-shaped member is hollowand has a slightly larger diameter than the opposite end. To deliver theC-shaped support band, the support band can be stretched into a linearform and advanced through a delivery catheter (e.g., using a pusherelement). In particular, the distal end of the delivery catheter can bepositioned adjacent the chordae tendineae such that when the supportband is advanced out of the distal end, it wraps around the chordaetendineae. After the support band is deployed from the distal end of thedelivery catheter, a clamping device that is designed to engage theC-shaped support band and urge the ends of the support band together canbe inserted into the heart (e.g., through the delivery catheter, theintroducer sheath, or through a separate catheter). The clamping devicecan be used to urge one end of the support band into the hollow oppositeend of the band. The ends can be crimped so that the support band formsa ring-shaped support band (e.g., using the clamping device or otherdevice). In other embodiments, the hollow end of the support band cancomprise a shoulder that engages an angled collar on the other end ofthe support band when the ends are urged together, thereby form asnap-fit connection. With the ends of the support band secured to oneanother, the support band can be positioned around the native leafletsof the mitral valve (e.g., using the clamping device or otherpositioning device) as a balloon catheter delivers a THV. Uponexpansion, the THV will pinch the native valve leaflets between theouter surface of the THV and the interior surface of the support band,thereby securing the THV within the mitral valve.

In still another embodiment, the support band includes one or moreclamping or fastening devices that can be used to clamp or fasten thesupport band to the native leaflets of the mitral leaflets. For example,the clamping or fastening devices can comprise spring-loaded clamps,anchoring members having one or more hook or umbrella-shaped barbs,clasps, or other such clamping or fastening mechanisms. In thisembodiment, the support band still has a substantially fixed diametersuch that when the THV is expanded into the interior of the mitralvalve, the THV causes the native valve leaflets to be pinched againstthe interior surface of the support band, thereby securing the THVwithin the mitral valve. In still other embodiments, the THV itself caninclude one or more clamping or fastening devices designed to clamp orfasten the THV to the native leaflets of the mitral valve (e.g., any ofthe clamping or fastening mechanisms described above). In thisembodiment, the THV can be secured directly to the native leafletswithout the use of a support band or other support structure.

FIG. 29 shows one exemplary embodiment of a locking member that can beused for locking member 460 shown in FIGS. 19-27. In particular, FIG. 29shows locking member 600, which can be a clamp, such as an adjustable,C-shaped clamp with interlocking teeth around a portion of the clamp.The locking member 600 has two arms 610, 612, each formed withinterlocking teeth 620, 622. Interlocking teeth 620, 622 are configuredto lock the clamp in one or more positions of varying circumference whenpressure is applied to the two arms 610, 612 and pushes the armstogether. Referring to FIG. 23, the cord portions (such as portions 446,446) can be inserted into the interior 630 of the locking member 600.The arms 610, 612 can be pushed together and tightened so that theportions 444, 446 are secured in place (e.g., using a clamping deviceinserted into the left ventricle through the introducer sheath or usingthe pusher tube 462 modified to include a clamping mechanism). Theinterior 630 can additionally have grooves to increase the friction anddecrease the slippage between the locking member 600 and the portions ofthe cord secured therein.

FIGS. 30-37 depict another exemplary embodiment of a locking member thatcan be used for locking member 460 shown in FIGS. 19-27. In particular,FIGS. 30-37 show an adjustable locking member 700, which can be attachedto two portions of a cord, thereby forming the support band. As bestseen in FIGS. 30 and 32, the adjustable locking member 700 comprises atapered, plastic pin 710 that fits into a tapered, plastic snap ring720. When pin 710 and ring 720 are locked together, the adjustablelocking member 700 is prevented from moving relative to the portions ofthe cord that are captured within the adjustable locking member 700(e.g., cord portions 702, 704 in FIG. 30).

FIG. 31 illustrates an exemplary pusher tube (or adjustment catheter)730 that can be used to introduce, position, and lock the adjustablelocking member 700 in a desired position. The exemplary pusher tube 730in the illustrated configuration has a fork member 732, an unlockingpush member 734 that is extendable through the fork member 732, and alocking push member 736 that is extendable over the unlocking pushmember 734. Fork member 732 is configured so that it can move theadjustable locking member 700 over the cord portions to which it isconnected. In particular, fork member 732 can engage the adjustablelocking member 700 when it is positioned along the cord portions (butnot yet in a locked position) such that by moving the pusher tube 730 inone direction along the length of the cord portions, adjustable lockingmember 700 is also moved. By moving the adjustable locking member 700 inthis manner, the effective diameter of the support band formed by thecord and the adjustable locking member 700 can be modified.

Push members 734, 736 are slidably movable relative to each other andthe fork member 732 to effect locking and unlocking of the adjustablelocking member 700, as further described below. The unlocking pushmember 734 unlocks the adjustable locking member 700 from the lockedposition and the locking push member 736 locks the adjustable lockingmember 700 from the unlocked position.

FIG. 32 depicts the adjustable locking member 700, according to oneembodiment, in more detail. The pin 710 comprises pin slots or holes 712(which accept the cord portions) and locking members or flanges 714(which extend outward to secure the pin to the ring in a lockedposition). Ring 720 comprises ring slots or holes 722 (which accepts thecord portions) and pin receiving hole 724 (which receives the pin tosecure the pin to the ring in a locked position). The locking members714 are deformable to allow the pin member to be inserted throughoutring member and form a snap-fit connection sufficient to hold the ringmember on the pin member.

FIGS. 33-37 depict the relationship between the adjustable lockingmember 700 and the pusher tube 730, according to one embodiment, andtheir functions relative to one another. As discussed above, the pushertube 730 comprises fork member 732, unlocking push member 734, andlocking push member 736. FIG. 33 shows the pusher tube 730 in moredetail. Both the unlocking push member 734 and the locking push member736 are slidably movable within the pusher tube 730 along thelongitudinal direction identified by the arrows shown in FIG. 33. Theunlocking push member 734 is desirably a solid member that is sized tofit within the locking push member 736, which is desirably cylindricalwith a longitudinally extending hollow section or lumen for receivingthe unlocking push member 734.

FIG. 34 shows the adjustable locking member 700 with the pin 710 and thering 720 locked together. In the locked position, the cord portions 702,704 pass inside the ring 720 and around the pin 710 (through the ringholes and pin holes) and are captured between these two components. Thecord portions 702, 704 are held in place relative to each other, and thepin 710 and the ring 720 are held in place relative to the cord portions702, 704 by the friction created at the surface interfaces.

Referring to FIGS. 35 and 36, to unlock the adjustable locking member700, the fork member 732 is inserted between the pin 710 and the ring720, and the unlocking push member 734 is extended from the pusher tube730 to push the pin 710 and the ring 720 apart. The fork member 732holds the ring 720 in place, while the unlocking push member 734 applieslongitudinal pressure against the tip of the pin 710, forcing it out ofthe ring 720. The unlocking push member 734 is desirably sized so thatit can fit at least partially through the pin receiving hole 724 toassist in unlocking the pin 710 and the ring 720 from one another. Oncethe pin 710 and the ring 720 are separated, the adjustable lockingmember 700 can be moved relative to the cord portions 702, 704 in orderto adjust the diameter of the support band formed by the cord portions702, 704.

Referring to FIG. 37, the manner in which the pusher tube 730 can beused to secure the pin 710 and the ring 720 together is shown. The forkmember 732 is placed at the far (distal) end of the pin 710 and thelocking push member 736 is extended from the pusher tube 730. Thelocking push member 736 is configured with a cylindrical surface that issized to mate with the area of the ring 720 that surrounds the pinreceiving hole. While the fork member 732 holds the pin 710 in place,the locking push member 736 forces the ring 720 onto the pin 710 andlocks the pin and the ring together. Once the adjustable locking member700 is locked, the frictional engagement of the adjustable lockingmember with the cord portions maintains the position of the adjustablelocking member relative to the cord portions 702, 704. The three-pointconnection system described above permits a surgeon to perform fineadjustments of the diameter of the support band around the chordaetendineae and around the outflow side of the native leaflets of themitral valve.

FIGS. 38-39 depict another exemplary embodiment of a locking member thatcan be used for locking member 460 shown in FIGS. 19-27. In particular,FIG. 38 shows an adjustable locking member 900 having a generallycylindrical body with two lumens (or apertures) 910, 912 formed thereinthat extend from a top surface 902 to a bottom surface 904 of the body.In the illustrated embodiment, and as best seen in the cut-away portionof FIG. 38 showing the lumen 912, the interior of the lumens 910, 912comprises a plurality of teeth (or collars) 920, 922 that are angledtoward the bottom surface 904. The teeth 920 can have some flexibilityand be formed to allow a cord portion, such as cord portion 930 or cordportion 932, to slide through the lumens 910, 912 in a first direction,but not in an opposite second direction. In other words, the teeth 920,922 of the adjustable locking member 900 allow for one-way movement ofthe locking member 900 along the cord portions 930, 932. In this way,the adjustable locking member 900 can be used to securely form thesupport band and allows for the diameter of the support band to beadjusted to its desired size.

FIG. 39 shows an exemplary embodiment of a pusher tube 950 that can beused with the adjustable locking member 900 (e.g., the pusher tube 950can be used as the pusher tube 462 shown in FIGS. 19-27). The exemplarypusher tube 950 includes lumens 960, 962 through which the cord portions930, 932 can extend. In a particular embodiment, the lumens 960, 962have a sufficiently large diameter and a smooth interior that allows thecord portions 930, 932 to more easily slide therethrough. In theillustrated embodiment, the pusher tube 950 further includes a rotatableblade 970 at its distal end 902. The rotatable blade 970 can berotatable about a central axis of the pusher tube 950 and connected toan interior rod member 972 that extends through a central lumen of thepusher tube 950. A handle (not shown) can be attached to the interiorrod member 972 at its proximal end and allow for an operator to manuallyrotate the rotatable blade 970 in order to sever the pusher tube 950from the adjustable locking member 900.

Other methods of delivering a support band and THV to the mitral valveor any other heart valve are also possible. For example, in certainembodiments, the support band and the THV are delivered surgically tothe desired heart valve (e.g., in an open-heart surgical procedure).Furthermore, in certain embodiments in which the support band and THVare delivered surgically, non-compressible THVs are used.

Having illustrated and described the principles of the disclosedtechnology, it will be apparent to those skilled in the art that thedisclosed embodiments can be modified in arrangement and detail withoutdeparting from such principles. In view of the many possible embodimentsto which the principles of the disclosed technologies can be applied, itshould be recognized that the illustrated embodiments are only preferredexamples of the technologies and should not be taken as limiting thescope of the invention. Rather, the scope of the invention is defined bythe following claims and their equivalents. We therefore claim all thatcomes within the scope and spirit of these claims.

1. A method of treating a deficient mitral valve, comprising: deliveringa support band to a position within a left ventricle adjacent an outflowside of a native mitral valve such that the support band surrounds atleast a portion of one or more native leaflets of the native mitralvalve; delivering a prosthetic heart valve into an interior of thenative mitral valve, the prosthetic heart valve comprising a collapsibleand expandable stent and a valve structure formed with pericardialtissue, the prosthetic heart valve being separate from the support band;and expanding the prosthetic heart valve within the native mitral valveso that the native leaflets of the native mitral valve are frictionallysecured between the support band and an outer wall of the stent of theprosthetic heart valve.
 2. The method of claim 1, wherein the supportband at least partially surrounds the chordae tendinae of the mitralvalve.
 3. The method of claim 1, wherein the support band comprises acord and an adjustable locking member, the adjustable locking membersecuring at least two portions of the cord to the adjustable lockingmember to form the support band.
 4. The method of claim 3, wherein theprosthetic heart valve is delivered into the left ventricle before thediameter of the support band is fixed.
 5. The method of claim 1, whereinthe support band comprises a shape-memory metal.
 6. The method of claim1, further comprising disconnecting the support band from at least onedelivery catheter once the one or more native leaflets of the nativemitral valve are frictionally secured between the support band and theprosthetic heart valve.
 7. The method of claim 6, wherein thedisconnecting comprises cutting through material used to form thesupport band.
 8. The method of claim 1, wherein the stent is aself-expandable.
 9. A method, comprising: forming a partial loop aroundat least some of the chordae tendineae of a native mitral valve with acord of biocompatible material; securing a locking member to at leasttwo portions of the cord to form a closed loop; positioning anexpandable prosthetic heart valve into an interior of the mitral valve;and expanding the expandable prosthetic heart valve, thereby causing anexterior surface of the expandable prosthetic heart valve to urge nativeleaflets of the mitral valve against an interior surface of the loop andto frictionally secure the expandable prosthetic heart valve to thenative leaflets of the native mitral valve.
 10. The method of claim 9,wherein the act of securing a locking member to portions of the cordcomprises: positioning the locking member over the portions of the cord;advancing the locking member along the portions of the cord, therebydecreasing a diameter of the loop formed by the cord and the lockingmember; and securing the locking member to the portions of the cord toform the closed loop, wherein the closed loop has a substantially fixeddiameter and an inner diameter of the closed loop is substantially equalto an outer diameter of the prosthetic heart valve when in an expandedconfiguration within the native mitral valve.
 11. The method of claim 9,further comprising cutting through portions of the cord to release theloop formed by the cord of biocompatible material and the lockingmember.
 12. The method of claim 9, wherein the locking member isattached to the at least two portions of the cord occurs before theexpandable prosthetic heart valve is expanded.
 13. The method of claim9, wherein the act of attaching the locking member to the at least twoportions of the cord occurs after expanding the expandable prostheticheart valve.
 14. The method of claim 9, further comprising: unsecuringthe locking member from the portions of the cord prior to expanding theprosthetic heart valve; adjusting the diameter of the loop by moving thelocking member along the portions of the cord; and re-securing thelocking member to the portions and forming a second loop with asubstantially fixed diameter of a different size.
 15. The method ofclaim 9, wherein the act of forming the partial loop around the chordaetendineae of the patient's heart is performed using one or more deliverycatheters inserted through the aortic arch of the patient.
 16. Themethod of claim 9, wherein the act of forming the partial loop aroundthe chordae tendineae of the patient's heart is performed using one ormore delivery catheters inserted through an opening in the leftventricle of the patient.
 17. A method, comprising: advancing a firstend of a support band out of a distal end of a first catheter, thesupport band at least partially encircling the chordae tendinae of anative mitral valve; receiving the first end of the support band in adistal end of a second catheter; advancing a locking member over thesupport band to form a loop; and adjusting a diameter of the loop formedby the support band and the locking member to a desired diameter andsecuring the locking member to the support band.
 18. The method of claim18, further comprising: advancing an expandable prosthetic heart valveinto the mitral valve and the interior of the loop formed by the supportband and the locking member while the prosthetic heart valve is in acompressed state; and expanding the expandable prosthetic heart valveinto an uncompressed state, thereby causing one or more native leafletsof the mitral valve to be frictionally secured between the loop and theexpandable prosthetic heart valve.
 19. The method of claim 18, whereinthe first and second catheters are advanced percutaneously through theaortic valve to provide access to the native mitral valve for deliveryof the support band.
 20. The method of claim 18, wherein the act offorming the loop comprises: advancing the distal end of the firstdelivery catheter into the left ventricle of a patient so that a distalportion of the first delivery catheter substantially circumscribes afirst half of the patient's chordae tendineae; advancing the distal endof the second delivery catheter into the left ventricle of the patientso that a distal portion of the second delivery catheter substantiallycircumscribes a second half of the patient's chordae tendineae and sothat a distal end of the second delivery catheter contacts a distal endof the first delivery catheter, thereby forming a delivery catheterjunction; advancing the first end of the support band through the firstdelivery catheter, across the delivery catheter junction, and into thesecond delivery catheter; and retracting the first delivery catheter andthe second delivery catheter from the left ventricle of the patient.